BIKE: Hydration can be fatal

[Jeb Boyt]

It is hard to believe that these people drank so much that they actually 
gained weight while running a marathon.  But then, I sweat like a pig when 
working out.

Jeb

----Original Message Follows----
From: Patrick Goetz <pgoetz>
To: Austin Bikes <forum>,Jen Duthie 
<jduthie>,Adam Rogoyski <rogoyski>
Subject: BIKE: Hydration can be fatal
Date: Thu, 14 Apr 2005 11:08:47 -0500

http://www.nytimes.com/2005/04/14/opinion/14thu2.html?th&emc=th


Brain-Dead From Sports Drinks
Published: April 14, 2005

For years now, we've been hearing about the importance of hydration to avoid 
heat stroke during prolonged exercise in hot weather. Now, it turns out, too 
much hydration can kill you.

A study published today in The New England Journal of Medicine should give 
weekend warriors reason to rethink the wisdom of quaffing vast amounts of 
water or sports drinks while exercising vigorously - at least if they are 
engaging in such endurance tests as a marathon. The study found that a 
marathon runner could dangerously dilute the blood with an overdose of 
liquids, risking a coma and even death. The problem has also been detected 
during long military maneuvers, extended bike rides and blistering hikes 
through the desert.

An article by Gina Kolata in The Times today describes the slow and belated 
recognition of the problem. A South African expert who has been warning of 
the dangers for more than two decades told Ms. Kolata that he had not found 
a single case when an athlete had died from dehydration in a competitive 
race, but that some people had sickened and died from drinking too much. 
Typically, an overdose of water dilutes their blood and reduces the 
concentration of sodium. Water enters the cells, causing them to swell, and 
engorged brain cells press into the skull; such pressure can lead to 
confusion, seizures and a loss of vital functions.

All too often, friends, coaches or emergency personnel assume that the 
problem is dehydration and administer yet more liquid, making the problem 
worse. The best treatment is a small volume of a concentrated salt solution, 
given intravenously, to increase blood sodium concentrations. Sports drinks 
containing electrolytes may not help much as they are mostly liquid 
themselves.

In the 2002 Boston Marathon, for example, a 28-year-old woman found herself 
exhausted after running for five hours and gulping sports drinks along the 
way. Wrongly assuming that she was dehydrated, she chugged down 16 more 
ounces of a sports drink. She promptly collapsed and was later declared 
brain-dead. The concentration of salt in her blood was found to be lethally 
low.

In the study published today, researchers at various Harvard-affiliated 
institutions tested 488 of the nearly 15,000 runners who completed the 2002 
Boston Marathon. They found that 13 percent had blood with abnormally low 
sodium levels, and that three runners were in danger of dying. It was not 
the elite runners who were at risk - it was those who had taken four hours 
or more to finish the race, allowing plenty of time to imbibe excess fluid.

Sports authorities have already issued warnings and tips to avoid excessive 
drinking, and rescue workers in the Grand Canyon now carry devices to test 
collapsed hikers for low blood sodium. But the solution is for overly eager 
endurance runners and hikers to forget the old mantra that they should 
drink-drink-drink. Too much liquid can be lethal.



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